Questions to Chapter 2.1.1
| Here are some raw questions | ||||||
| 1. Give examples and orders of magnitude for carrierr concentrations in various materials including the temperature dependence | ||||||
| Metals: k = 1....3 electrons per
atom, n = k · density of atoms = k · (specific weight / atomic
weight). Examples for n = 1,2,3,.... (????) n(T) independent of T; exception (semimetals, ...) electrolytes (????) graphite, ??? semicnductors Superconductors |
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| s and crystal lattice defects. What kind of defects would influence s? Most effecient defects? | ||||||
| Point defects, dislocations, grain
boundaries, precipitations, second phases, ... Point defects; l -argument. |
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| T-dependence or Al resitance. Give graph.
Compare to rule of thumb Resistivity of Al lines on ME circuits limits maximum length to l = 1 mm because R·C has to be kept below a certain value. Assuming that R and C are proportional to l; would it make (commercial) sense to replace the Al by a superconductor if length of 5 mm are required? Note: If a superconductor is used, the device needs to be cooled to < 100 K. |
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| If theAl resistance decrease about 5 fold, it makes no sense | ||||||
| Figure of merit: High voltage cable, must withstand load of ... Own weight also important,..., price, resistivity,... | ||||||
| ???? | ||||||
| Multiple choice questions | ||||||
| Chapter 2.1.1 Metals | ||||||
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| Chapter 2.1.2 Alloys | ||||||
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| Chapter 2.1.3 Non-metallicCondctors | ||||||
| In addition: MC Questions from "Fischer" p. 155 | ||||||
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